Railway sleeper



Jan. 16, 1951 A. BAGON 2,538,437

RAILWAY SLEEPER Filed April 1'7, 1946 UNITED STATE Thisiinvention relates Patented Jan. 16, 1951 s PATENT OFFICE 'RAILWAY SLEEBER A'br-am'Bagon, Brussels, Belgium `:Application April 17, 1946, Serial N o. 662,711

InBelgum October .13, 1942 'Section 1, Public Law 690, August 8 1946l Patent expires October 13, 1962 to asleeper constructed mainly- .of concrete or like rigid materials, Yand .reclaim-s.' (checa-87) vintended more particularly for use'inlaying rail ftracks, although it may likewise be yadvanta- ,igeously `utilised as a structural element in cases Where the working conditions are similar.

v lt 'has' been fobserved that `the satisfactory bey,l;1aviourrof-rasleeper on thev track requires that a rail should be capablefof undergoing, in relationzto the other rail, variations of level rof the lorderofiromr -to 7.5 millimetres, and then resuming its original position exactly. V4Vfithont any excessive fatigue of the sleeper Jresulting,-there- `cfronfi. ,'Io this end ione test of :strength consists infsubjecting'onev-end or thelsleeper to aiternating bending while the sleeper vis ,rigidly Sheld at the :other end. A good .sleeper should `leerable to ,.endure, without deterioration., several million Yalternating deflectionsfof a .total amplitude of at: least` l5 millimetres.

Known monolithic sleepers cannot stand this fliesltitir .they are ltoo rigid. YMixedsl'eepers have .zon the other 4hand .been .proposed which vcomprise Vrigid.sections alternating, in the #direction of 'the 'length of `the sleeper, .with sectionsroi more de- Iornlable material, the various elements 4being Aheld together 'by :metallic framing orreinforcing ,pins -or rods. Suchmixed ,sleepers .do indeed permit of relative Avariations of level between the two rails, but theydo not ensure :the elasticre- 'turn into `,the initial v,posi'tiomancl .theyaso have `the 4disadvantage *that 'the joints. between the sucf cessive sections `open when the 'sleeper undergoes 'vle'formations Fromth'isit results on fthexone "hand that'therail is not restored strictly to its position inclined "by 1/20 to the vertical, which may have disastrous-consequences for the running and wearing conditions` of the rolling stock,

"While on fthe other hand the opening' ofthe joints permits the penetration of water and 'of 'corro` sive agents; which compromise" theframing or reinforcement, as well .as solid bodies, which k'winch may :render the sleeperv useless.

'cr'der to'c'o'mpiy 'withw'tiie renditions set forth and to eliminate the disadvantages of the known sleepers, a sleeper should exhibit elastic s 2 nised variations of level of one rail in relation Ato the other, and Ashould ensure the elastic Vreturn of theseeper fto fits original form and yposition as soon :as the -stress has ceased, so as Yto maintain l'the wcorrect inclination ofthe rails. According to the present invention this result is attained by constructing a railway or like sleeper comprising transverse `sectionsof yconcrete Lorfthe like, alternating with intervening trans- .verse sections `ol. a material -of greater elastic compressibility, these various elements being assembled .by means of a longitudinal framing or reinforcement, vthis sleeper being essentially characterised by the feature that by placing under tension 'this framing, which passes freely Ythrough the intervening elements, andthe ends :of :which are-fixed to the end elements, the cornposite unit of freely 'juxtaposed elements is placed 1ina statezof'initial stress, which ensures its elastic deformability under the action of the stresses occurring inservice. l Under test,1a sleeper-"thus yconstructed has'behavedlin aremarkable manner having been 4sub- 'jected `to l125 million vibrations of an amplitude of l19 millimetres, it exhibited no apparent sign oirfatigue after the test. The initial stress cre'- v-atetl :by 'the vtensioning `of the 'framing ensures :the stability of form of the composite unit `and prevents .the existence `of 'tensile'stressesin the ,latter `vvhendeiorrnations occur inserviceyso that -rno separation of the constituent elements takes jplace, that isfto say, the sleeper remains strictly continuous, like. a beam consisting of a single material. 4 :thenombined action of theme-constraint v:and `ofithe elastically more deformable Ainterven- -Ling elements,v 'real `resilient jointsare obtained,

' which, :as'tests'have demonstrated, exhibit pracdeformability under the action of the stresses l tically no fatigue 'under the action of vrepeated v,bending :of the sleeper, whereas Iallvthe known niixed` sleepers quickly failed as al result of fatigue.

The ltensioning of the reinforcement may 'be effected. by Vany .appropriate means, particularly by exerting fa pull, .byv means of aV jack or the finent'oi fthe :sleeper Viwhen thev desired tensionattained. This tension may likewise be attained by separating the elements to which the endsA of the reinforcement are suitably anchored, the free space thus produced'between the elements vof the sleepervbeing lled upgwith Wedging blocks, and this separation of thefanchoring 'points of the .interposed members 3.

metallic tie-rod 5, which is subjected to tension which is designed to undergo vertical deflections' only, a plurality of reinforcements or `tie-rods might be provided, located in the same horizontal plane, though the provision of one framework only, formed of a single tie-rod or of a bundle of wires, presents the advantage of remaining without influence upon the elastic deformations Vin all directions.

Other details and advantages of the invention will appear from the description of an example of construction, given hereinafter by way of illustration with reference to the accompanying drawing, in which:

Figure l is a longitudinal sectional view on line I-l of Figure 2 in the direction in which the arrow points, the tie rod being shown in elevation and the position assumed by part of the railclamping means being shown in dotted lines.

Figure 2 shows a plan view of the same. The sleeper illustrated is composed of two blocks -or battens l of concrete, designed to support the rails 9 fastened by bolts i0, an intermediate element 2 of smaller cross section, also of concrete, and interposed pieces 3 of a material of much lgreater elastic compressibility, preferably Wood or wood-like material, placed between the battens l and the central element 2 andrprovided' with suitable hoops 8. The five independent elements I, I, 2 and 3, 3 are traversed by a longitudinal bore 4, which is located in the axis of the In this duct is lodged a and xed at its'ends to theblocks I by suitable anchoring means, this being conventionally indicated in the drawings by assuming that the ends of the tie-rods are screw-threaded and provided with nuts 6 and lock-nuts 1, by means 'of which the requisite longitudinal compression of the composite unit is maintained. The bore 4 may be lined with a protective sheath for the lframework 5.

In the sleeper thus constituted the blocks l alone effect the transmission of the loads to the ballast, while the central element 2, of smaller cross section, establishes, with less rigidity, the connection between the blocks.

The combined action of the pre-stressed tierod' and of the interposed pieces of wood 3 imparts to the sleeper its elastic deformability -under the action of the stresses occurring in service. Moreover the sleeper behaves like a really continuous member, and the interposed elements 3, the' entire cross section of which vparticipates in the elastic work of the sleeper, prevvent the occurrence of excessive tensions, which would-occur if discontinuities took place between the various elements of the sleeper, and ensure the unit having the requisite strength to resist dynamic stresses.

Thanks to the elastic articulations, therefore, one end of the sleeper can undergo a pronounced change of lever in relation to the other, the sleeper resu'mingits original form as soon the force that has produced the variation of., level ceases to act. The cant or inclination of l in 20 to the} vertical that it is desirable to give to railway rails will therefore always be reliably restored.

Various constructional modifications may be made in the sleeper without going outside the scope of the invention. Thus, although blocks of wood have given very'good results, it is possible to replace them by some other compressible and resilient material, such as synthetic resin, or by strong springs. The tie-rod may consist of a bundle of wires, and the anchoring thereof may be effected in any appropriate manner. Its ends might for example be xed and tensioned by means or devices, or might even'be embedded in the two blocks, would be held apart -by jacks while the interposed elements composed of supplementary parts, were being put in position and hooped.

'The term concrete is employed here in a broad sense, and covers cement, as well as any other agglomerate having a basis of stony material. The :term railway sleeper covers also the structural element according to the invention when used for other purposes. WhatI claim is: 'fl

l. 'A railway sleeper having the properties oi' an elastic beam, comprising spaced concrete railsupporting sections and at leastv one intervening concrete section, filler blocks of wood-like material of greater elastic compressiblity than concretelying between successive concrete sections, all of said sections and blocks being providedwith aligned bores therethrough, said bores lying in the neutral zone of said sleeper, a longitudinal reinforcing 'tension member extending freely through all of said aligned bores and means securing its ends in clamping engagement with the outer end portions of said rail-supporting sections, said member being tensionedto provide a substantial compressive Vforce holding said sections and blocks in contact with one another with sucient force so that said sleeper under exure will be elastically deformed in the manner of afunitary elastic beam. K

2. A railwaysleeper in accordance with claim 1, in which the filler blocks are Abanded by hoops.

ABRAM BAGON.

REFERENCES orrlazi4 y The following references are ofrecord in the file of this patent: l

1,410,135 Iekes 1 Mar. 21, 1922 

